With animals, practitioners are freer to use their judgement. Animals not only die with their germs, but are often euthenized. Notice what happened with the recent bovine infections in England. One excellent way to stem the spread of infection is to kill and burn the infected.
"What, no prescription? Don't you love me, doc? Do I have to call hospital admin to get my antibiotics, or shall I call my lawyer?"
Things are complicated with people--you can't just shoot them.